The invention pertains to an underwater detonating device for igniting explosive charges, comprising at least two independent safety provisions as two water pressure safety devices and a locking pin safety arrangement with a rotor carrying a detonator, which rotor can only be moved into a live position by release through a controlled sequence of steps.
Backstein in U.S. Pat. No. 4,038,901 issued Aug. 2, 1977 discloses a submergible detonating device, which can be pulled by a tow cable, and a detonator gripper is employed for underwater cutting of anchor chains of sea mines or the like. The detonating device is provided with a release plate to be actuated by the anchor chain, and upon impact with a sufficiently high mechanical pressure the plate punches through a shear safety arrangement and thus releases the ignition mechanism, if previously the water pressure safety device had been actuated and had released an ignition needle blockage.
The known arrangement thus is provided with three safety provisions, which are to be actuated in the cited sequence for releasing the ignition, that is, a cutter pin safety device not itself secured for the release plate, a water pressure safety device for the ignition needle, as well as a shearing force safety devie, the release of which by mechanical forces directly results in starting the ignition.
It appears to be clear that such an underwater ignition device is well adapted as a detonator gripper pulled by a tow cable for the sweeping of mines; however, it cannot be employed directly for all possible tasks of explosive charges, wherein mechanical pressure action is undesired or not possible for any reasons.